With the advent of more frequent tampering of products packages in containers, it has become quite important to provide the public with some positive indication whether a purchased product has been tampered with subsequent to leaving the manufacturer's plant.
Products packaged in containers such as bottles have become quite vulnerable to tampering, consequently many tamper indicating systems have been devised. One such tamper indicating system for threaded bottles is disclosed in U.S. Pat. No. 4,511,053 which issued Apr. 16, 1985. This patent shows a metal closure that has a radially inward lower skirt portion that clamps against the upper portion of a plastic tamper indicating ring. The tamper indicating ring has a series of grooves around the lower skirt to facilitate assembly of the tamper indicating ring over the retaining flange that is located beneath the threaded portion of the container neck. Thus, special provisions have to be made for easing the lower portion of the tamper indicating ring over the container finish. Also, the metal cap skirt has to be specially designed to accommodate the upper portion of the tamper indicating ring. As a closure removal torque is applied to the closure, the upward force causes the lower portion of the tamper indicating ring to engage the under side of the flange on the container thus causing the ring to break along a weakened circumferential line.
Another example of a tamper ring-closure combination is shown and described in U.S. Pat. No. 4,493,427 which issued Jan. 15, 1985. The tamper indicating portion of the closure assembly is essentially "Z" shaped with a lower tongue resting under a flange beneath the container finish when in the installed position. The upper portion of the tamper indicating ring has a radially outwardly protruding ring that coacts with a portion of the closure inside. Retrograde rotation of the closure produces tensile and shear forces within the tamper indication ring thus causing it to break along a weakened section.
U.S. Pat. No. 4,503,986 which issued Mar. 12, 1985, describes a closure and accompanying tamper indicating ring. A series of vertically aligned bridges connect the lower and upper portions of the tamper indicating ring together. Subsequent removal of the closure from the container causes the upright bridges to shear thus severing the tamper indicating ring.